Secondary battery.



W. MORRISON.

SECONDARY BATTERY.

APPLICATION FILED JUNE 8, 1903.

916,575, Patented Mar. 30, 1909.

2 SHEETSSHEET 1.

W. MORRISON.

SECONDARY BATTERY.

APPLICATION FILED JUNE 8, 1903.

Patented Mar. 30, 1909. 2 SHEETS-SHEET 2.

cury would be dissolved and leave the support and fall upon the electrode below, leavingthe support unfit to receive and hold the zinc deposit.

The object of my invention is to provide a practical battery of the alkaline type, in

.which zinc is one of the elements, and which shall be capable of use for all the various purposes to which batteries may be put, and which does not have the recited or other disadvantages.

To this end my invention consists primarily in a secondary battery, in which and pointed out, reference being now hadto the accompanying drawings, in which:

Figure 1 is a perspective view of the complete cell, partly broken away to show the interior construction and arrangement. Fig. 2 is a plan view with the cover and solutlon removed, showing the positive electrode partly broken away and with the insulating protector partly in section. Fig. 3 is a cross sectional view of the complete cell. Fig. 4 is a detail view of a fragment or portion of the insulating protector. Fig. 5 is a detail View of the corner of the cell partly broken away, and in section, showing the negativeepole electrode consisting of a plurality of screens superimposed one upon the other and resting upon the bottom of' the cell. s

In carrying out my invention, and as con stituting one specific embodiment thereof, I provide preferably a metal cell A which may be of copper, iron, steel, or other suitable metal, within which I build up one upon the other in the bottom of the cell, a

number of screens of woven wire or perforated metal, designated at-B. These screens, which are preferably of copper, are preliminarily'treated by plating them with silver, copper, or other suitable metal to form a metallic, spongy and porous covering capable of holding a large quantity of mercury. I then fill the spongy covering with mercury by dipping the screens into a vat of cyanid of mercury and then again into a vat of metallic mercury. Care, however, should be taken to wash out the cyanid. These screens are then electroplated in a solution of caustic potash having zinc dissolved thereon, until a necessary quantity of zinc is depo sitedfupon the screens. The screens ,rso prepared ,are then deposited one upon the other in the bottom of the cell, which cell has been previously plated. and amalgamated on the bottom. .(Fig. A sufiicient number of these screens are so disposed .to form a negative-pole electrode C, of a suflicient thickness or depth. Above this negative-pole electrode is an insulating band I), to be more particularly described I provide a grid shaped protecting member I), of insulating material, having cells 0 passing through it from top to bottom. Upon the top of this member E is the positive electrode H of copper, silver, nickel, or other suitable material, of the character used in the well-known types of alkaline batteries. It should be preferably perforated, or so constructed as to permit the gas to pass above the negative electrode and permit the free circulation of the liquid.

As shown, the negative-pole electrode is made up of a number of superimposed screens 15, upon the bottom of the cellA. An insulating band D extends completely about the interior of the cell and rests against the sides thereof, the lower edge of said insulating band iestingupon the marginal edge of the negativepole electrodeand extending upward nearly to the top of the cell. The insulating protector E is placed upon the top of the negative-pole electrode and within the outer insulating band D. The positive electrode His placed upon the top of the insulating protector E and a second inner and insulating band J extending completely about the interior of the cell and resting against the outer insulating'band D, rests, at its lower edge, upon the marginal edge of the positive electrode. The cover D-sits within the cell A and bears upon the,

upper edges of thetwo insulating bands D, and J, so that when the cover is pressed downwardly and soldered in place firmly the outer insulating band presses the marginal edges of the negative-pole electrode firmly into place and the inner insulating band J pressing downward upon the positive electrode in turn causes the insulating protector E to firmly press upon the negativepole elctrode beneath, thus binding the va rious screens of the negative-pole electrode firmly together and to the bottom of the cell. If found desirable, thesevarious screens may be sewed together or soldered, or otherwise fastened together-{and the electrode support soldered to the cell itself, thus giving a greater amount of conductivity to the electrode support. and more intimate Min the solution isfirst deposited moms pole electrode firmly in lace, and the other purpose to subdivide the interior ofthe cell between the negative-poleand pointive electrodes into sections of such sire ass to con line the wash of the solution within con paratirely small areas, so that it the zinc in the. solution ahould become detached from the negative-pole electrode by the small amount oil wash still remaining, or otherwise it cannot shift such a distance as to gather together a sullieient quantity of zinc to. short circuit, or otherwise affect the. 0peration of the battery.

A conductor (z extends to and is connected with a binding post 7; which extends through the cover and is isolated illOItllIOll] and fastened thereto by insulating plates so secured in place as to prevent leakage. The other binding post 1/ is fastened to the me' lallic cell itself.

The solution may he of caustic potash or caustic soda; although I prefer the former. l prefer to purify the caustic potash by electroplating between insoluble electrodes, with a suitable electric current, until the greater portion of the sediment is deposited on the electrodes, or precipitated.

T he ncg'atiYe-pole electrode eupporl consists of a number ol wire screcns previously described, placed one upon the other in a sull'icienl number to provide a porous. open and conductingbed or receptacle for the reception of a suliicieut quantity of ziuc to give the desired discharge. The zinc is deposited, upon the upper screens, or may he deposited on all the screens, the screens with their openings permitting the residumu orforeign products to penetrate farther into the electrode. and maintain the greater part of the active portion of the electrode upon the top thereof. i

In the operation of the battery, and in the first-tillage the zinc having been previously eleetroileposited,hydrogen is liberated and thegiositire eleotrode is oxidized inthe welllcnown zzntnner. In the discharge the zinc is dissolved into the solution and the posit ive-electri'ide is reduced in the well-lmown manner. It the electrmles are of greater capacity than the solution employed, the Ht)- .lntien will dissnlve and take up the nine to its-ultimate capacity and then the remainder of the zinc will )e oxidized in the further continued discharge and consequent generation of current, this portion of the Zinc re.- maining as an oxid of Zinc in the negativepole electrode. And it is moparent that the positive electrode will be still further re dueed. It is also apparent that as the solution gradually loses its capacity to rediasolve and take up the zinc, the quantity of oxid of zine in the negative-pole electrode will gradually increase in the operation of the battery: In the-second char e the zinc upon the mum, more and more oi the oxid ol' xinc remains in and upon the positive electrode.

in my very early e zperi1ueulm on. my present lype ol' hallery. l deposilcd 7 upon the bottom of the metal cell but tound that the movements oi the battery, .-.:u:l1 as ii would receive in automobile work, would cauw the solution to wash over the zinc and detach a part of it from its support and wash it lo one side oi the cell where it would short circuit the electrodes. 'l liifi 11clion would be facilitated by charging the battery too rapidly. as the zinc would be spongy and loose and thus more readily detached and shifted. l then tried one screen reeling upon and held against the botiom ol' the cell. but soon l'ouud that although the zinc bound ltsell into and around the screen, a sediment deposited l'rom lhe solution and possibly 'l'rom the positive electrode settled upon the top oi the .x'll't'il'l. l olinlllpj a coating which llHWt'llKtll the uecexaary adherence and density of the zinc deposit. and this led to the prori io11 of a number ol' screens which proridcd a bed to hold the zinc. and permit the sediment to penetrate larther into the electrode support. 'lheret'ore. in selecting these screem care should be taken to select a screen with sutlicient 111e ;h to provide free openings for the sediment and at the v ame time hold the Zinc. By this means l t'ound that the. zinc was kept clean and practically tree from foreign sediment. and

'as held in place permitting free circulation 'ol the solution. is in the discharge the zinc is new up into the solution the sediment s ttles farther toward the bottom of the cell and in the charge 'l resh and clean zinc is depositml. comparalively free from sediment. on the lop oi the electrode. The -c'onli1luerl charge and discharge assists the natural tendency toward seltlemenl oi the sediment farther into the electrode leaving the top portion oi the electrode comparatively tree from sediment and in condition t receive the zinc. This screen 'tmnratiou also, by reason of its mesh, tends to prc-x'ent the sediment from being; washed out of the szrreen into the solutio [the negativepole electrode is thoroughly amalgamated before being placed in the cell. and this amalgam is preserved in each suc cesoive charge by providing;' an excess of mercury in the bottom of the cell. it is advisable to bindthe screeua lightly together and to the bottom of the cell so ll1at-tl1e mercury may freely find its -way lrom one. screen to the other and thus maintain I porous nature of the same.

& 916,575

thorough and complete amalgamation. I found that under the reducing action of the charge on the negative-pole electrode. the mercury adheres and binds with a la rge proportion of the sediment, and also with the electrode itself, maintaining a thorough amalgamation. for the, reception of the de p os ited zinc and to prevent local action. This thorough amalgamation is made pos sible by reason of the lochtion of the electrode in the bottom of the cell in substan tially a horizontal position, and by the This is evident because the mercury may distribute itself through the electrode and cannot fall off from the electrode. The mercury is always in contact with the electrode.

After all ofa'ay experiments, I found that it was advantageous, in traction work, to provide means for preventing the wash of the solution upon the top of the negativepole electrode. This is accomplished by providing a grid of insulating material ha ving openings extending through it which subdivide the solution into small bodies, thus interrupting the wash of the solution and limiting that wash within small areas. Thus if. any portion of the zinc does become detached, it will be a small portion and will be'carried only a short distance and cannot. therefore do much harm.

From the foregoing it will be readily apparent that as the zinc contained in and upon an electrode in the bottom of the cell, it is in such a position that gravity tends to hold the zinc upon its support, and has no I tendency to remove it therefrom, as in the case where the electrodes are vertical, or when the negative-pole electrode is above the negative. And when the zinc is dissolved iir the solution and deposited back upon the electrode in the bottom of the cell, it is deposited in the direction of gravity upon the same relative position as before unatl ected by the variation of density of the solution. \Vhcreas, as previously explained, when the electrodes are vertical the variation of density of the solution causes the greater portion of the zinc to be deposited at, the point of greatest density causing the deposit. of zinc more and more toward the bottom of the electrode with each successive charge. Nor can the variation of density of the sohitionhave any effect when the electrode in the bottom of the cell because .then the area of greatest density of the solution is directly upon and through the electrode. As gravity tends to hold the zinc in place in and on theelectrode in the bottom of the cell, and as the zinc is previously deposited in asutlic'ient quantity for the capacity of the cell, and as the solution can continue'to-oxidize the zinc, to generate current in the operation of the battery, after it has become incapable of dissolving the zinc into the solution it is evident that a much smaller quantity of solution is necessary, very materially reducing the weight, bulk and costof the battery.

The alkaline solution cannot be neutralized by the zinc, as it generally requires about four or more molecules of hydrate of sodium or potassium to dissolve one molecule of zinc. This being the case, the solution is always strongly alkaline, and is capable of conducting the current in a satisfactory manner after it is saturated with the zinc, and the action of the battery then oxidizes the zinc, but does not dissolve it. It is thus evident that but a small amount of zinc will be dissolved by the electrolyte, the best results being obtained by the rapid charge and discharge of the battery. In the discharge the zinc is either dissolved into the solution or oxidized on the negative-pole electrode, separating and liberating the mercury, which tends to fall farther into the perforated electrode support. But in the charge, when the zinc is re-deposited upon the electrode in the form of metallic zinc and when the oxid of zinc in the electrode is reduced to metallic zinc, the tendency is to absorb the mercury back. again into and throughout the mass of metallic zinc to pro vide an amalgam. If any of the mercury is oxidized during the discharge or removed down farther into the electrode, it is reduced to metallic mercury in the charge and absorbed up again into and through the electrode. Thus in each and every charge the electrode. is maintained in proper condition to do the work. This result is not possible when the electrodes are vertical as the mercury tends to leave the electrode by gravLat-ion, oxidization and washing off, as previously described.

l have shown and described herein the structure which l have found gives the best results and produces an operative battery, and it will be understood as to those features hereinshown and described, but not claimed, that I reserve the right to claim the same in other applications tiled concurrently herewith. i v

I am aware that electrodes of batteries have been positioned horizontally and arranged, in the bottom of the cells in many other kinds of batteries, but I \V hat I claim as my invention is;

1. ln an electric reversible galvanic battery in which there is a suitable alkaline solution, a negative-pole electrode at or near the bottom of the cell, zinc in contact with the positive electrode, above the negative-pole electrode and insulating means located between said electrodes adapted to subdivide the entire body of the electrolyte between said electrodes, said zincbeing greatly in excess of that which the electrolyte can dissolve, whereby the excess a positive electrode" of zinc isoxidiz ed by said electrolyte without dissolving,-thereby producing an electric current.

:2. In an electric reversible galvanic hattery in which there is a suitable alkaline solution, a negative-pole electrode at. or near the bottom-of the cell, zinc and mercury in cont-act with said electrode, a positive electrode above the negativepole electrode and insulating means located between said electrodes adapted to subdivide the entire body of the electrolyte. between said electrodes, sai'dzinc being greatly in excess of that which the electrolyte can dissolve, whereby the excess of zinc is oxidized by said'electro lyte Without dissolving, therebyproducing an'electric current; c

3. In an electric reversible galvanic battery-in which there is a suitablealkaline solution zinc as the positive active element, a negative-pole electrode so disposed at or near the bottom of the cell in a substantially horizontal position that gravity tends to causeihe active material to remam in contactwith the negative-pole electrode, a positive electrode above the negative-pole electrode said zinc being greatly in excess of that which the electrolyte an dissolve, whereby the excess of ziuc is oxidized by said electrolyte without dissolving, producing an electric current.

4. In an electric reversible galvanic battery in which there is a suitable alkaline solution, zinc as the positiveactive element, a negative-pole electrode disposed at or near the bottom of the cell in substantially a horizontal position so that gravity tends to cause the active material to rcmainin contact'with the negative pole electrode. and a positive electrode above the negative-pole electrode,

together with mercury in contact with the negativepole electrode, the. mercury ire-- amalgamating the negative-pole? electrode in each successive charge, and insulating means between said electrodes adaptedto subdivide the body of electrolyte therebet'ween, said zinc being greatly in excess of that which the electrolyte can dissolve, whereby the excess of zinc is oxidized by said electrolyte without dissolving, thereby producing an electric current.

Signed by me at Chicago, Cook county, Illinois, this (3th day of June, 1903.

lVILLL-\M MORRISON.

ll'itnesses:

Cuas. C. Bummer, \V at. A. HAnonRs.

thereby 

